Lab values for Color Bridge swatches

[BC in the Bay]

Does anyone have a library of Lab values for the color bridge cmyk targets? I'd like to reference these values for some color conversions.

 

[Stephen Marsh]

Using the Photoshop colour picker, select the Pantone colour library book in question, then type the numbers of the target colour, then click back on the picker button and note the rounded L*a*b* values.

Or, one can add the colour in say InDesign, then change the model from CMYK to L*a*b* colour and note the values.


Stephen Marsh

 

[BC in the Bay]

Hi Stephen,

Thank you for your help...While that would be fine for a couple of colors, I need the values for all of the colors in the library. I'm really looking for a data file with all of the colors and their corresponding Lab values and I REALLY don't want to try to go through all of them manually and enter all of that data.

 

[Lukas Engqvist]

Note this is one of the BIGGEST CHANGES in CS6. Adobe is moving to the Pantone + libraries and colours will be in LAB and based on the Pantone+ libraries. There are CMYK breakdowns in books, but then the customer should use the PANTONE BRIDGE+ libraries. Just warning you so you can get polish up on your colour skills! This is a chance for us to flex our colour management muscles and show our customers that this is something we really understand!

 

[Stephen Marsh]

This question is tricky...

Working this out only with software, it is all about numbers and profiles. The Bridge values are fixed device dependent CMYK values. They are what they are, with no apparent device independent value. The Bridge values are attempting to make a "best match" to a Pantone solid L*a*b* target.

So, to find the L*a*b* values of a Bridge process simulation colour - one must assign/assume some sort of CMYK profile to the CMYK device values.


Stephen Marsh

 

[Stephen Marsh]

As mentioned previously, the Pantone Bridge library L*a*b* values in Photoshop are dependent on the CMYK working space and rendering intent values.

I imported the three Bridge library files into the ColorMunki software and exported out .CSV files that contain L*a*b* and spectral values of each of the three Bridge library files that ship with Photoshop CS5. I am not sure how/where these values came from, so I don't know how accurate they are or how much faith can or should be placed in them.

A .zip file is attached. Hope this helps.

EDIT: Forgot to mention, open the .CSV files up in MS Excel, OpenOffice Calc, Apple Numbers etc. as a spreadsheet.


Stephen Marsh